This invention relates to shoes and shoe sole inserts, and particularly to inserts for shoes of persons who experience prolonged periods of standing.
In recent decades, tremendous efforts and cost have been put forth for research into the complex action of the human foot during various types of activity, and into the engineering and design of footwear to maximize benefits to the wearer during these activities. Specifically, extensive research has been conducted for activities including basketball, aerobics, running, jogging and football, as well as desired characteristics of footwear for these activities. Even the activity of walking and the design of walking shoes has been explored relative to the complex foot action involved, but to a lesser extent. Moreover, substantial efforts have been made relative to the function and design of work boots relative to foot action.
One area of human activity which is not believed to have received the attention it deserves is that of prolonged standing. The nature and function of the complex human foot, and the effects on the leg and body during standing, are complicated. As is known by anyone who has had an occupation or activity involving long periods of standing, e.g., store clerks, factory workers, cashiers, theater personnel, or even persons who have had to wait in long lines such as at amusement parks, theaters, etc., standing can cause particular foot and leg fatigue and stress, even stress to the spinal area.
The foot is comprised of about 25 percent of all of the bones in the human body. The foot functions to support the weight of the body and to absorb shock and propel it forward during human movement. During standing, the arch of the foot functions much like the truss of a suspension bridge, the muscle/tendon junctions of the lower leg functioning to support the arch of the foot.
The strongest structure of the foot while standing is a high arched or neutral position. In this position, proper biomechanical posture and balance are maintained. When the arch of the foot collapses, greater stress is applied to the muscle/tendon junctions causing fatigue or even injury. Comfort while standing is correlated to balance and posture of the human body. When the muscles of the lower leg and foot begin to fatigue after extended periods of standing, people tend to become restless. They continually shift their body weight from leg to leg and flex their knees to alleviate concentrated stress to muscles and tendons.